The invention relates to a stapling (stitching) arrangement for a gathering and stapling machine, comprising: a machine frame; a circulating gathering chain for transporting printed products; a stapling carriage mounted on the machine frame for traveling with the gathering chain for stapling the printed products; at least one stapling head mounted for traveling with the stapling carriage and including a shaping element for shaping staples from a wire and a punch for punching the staples into the printed products; a bending device including a displaceable bending element for bending the staples when the staples are punched through the printed products; and drive means for the stapling carriage, the bending element and the punch.
Stapling machines of this type have traveling stapling heads, and permit the continuous stapling of products. The products therefore need not stop in order to be stapled, then accelerated. Stapling machines of this type are known in practice, and permit a comparatively high production speed. This kind of stapling machine is disclosed, for example, in the Applicant's Swiss patent publication CH-A-662 987.
These stapling machines are, however, designed for a fixed chain pitch of 21 inches, or 14/15 inches. The disadvantages of this are as follows: In the use of, for example, a gathering and stapling machine having a chain pitch of 21 inches products in a DIN format range of A5 through A3 and so-called double-sided products can be processed. For products of A4 format, however, the machine only operates with an output of 14,000 to 15,000 copies per hour. With a gathering and stapling machine having a chain pitch of 15 inches, products of A4 format can be processed with a significantly higher output of 18,000 copies per hour.
Products of A3 format or so-called double-sided products, however, cannot be processed in a machine having a chain pitch of 15 inches. A gathering and stapling machine having a variable chain pitch would therefore be desirable. As already mentioned, the known stapling machines having traveling stapling heads are limited to a fixed chain pitch, and cannot be converted.